This invention relates generally to a manually operative latch for a window sash of a double-hung window assembly and more particularly, to a novel latch capable of being installed internally in the sash window frame and which is releasable from externally of the window frame. Further, this latch is particularly suitable for a pivotal sash window.
A double-hung window assembly includes a window frame and a pair of window sashes reciprocal vertically in guide rails of the master frame jamb of the window assembly. Such a window sash also can be pivotally mounted in the window frame. Normal vertical movement of the window sash is maintained by latch mechanisms located at opposed corners of the window sash. Such a latch mechanism will include a latch bolt which can slide along the guide rails but which, while engaged in the guide rails, prevent pivoting of the window sash. The window sash is pivotal when the latch bolt is retracted from the guide rail by means of suitably installed pivot pins usually engaging sash balance mechanisms of the assembly.
Such pivotal window sash can be formed either of extruded plastic frame members or metal frame members joined at mitered corners to form a generally rectangular frame in which the glazing is mounted. In my co-pending patent application, a novel corner supporting and connecting member is described and illustrated which functions to establish and maintain the corner miter joint of a synthetic plastic sash frame. Said novel member also serves to mount a latch mechanism for a pivotal window sash. A notable feature of that latch mechanism is its internal mounting with a manual manipulative control button exterior of the sash frame.
The latch mechanism of the invention herein can be mounted internally of a pivotal window sash formed of either synthetic plastic or metal sash frame members. Yet, it is hidden from view other than for the exposed control button for retracting the latch bolt thereof from a guide rail so that the sash can be pivoted. The corner miter joint is established and maintained by right angle brackets or corner support means other than disclosed in my copending patent application.
The latch of the invention is economical to manufacture and easy to install and operate. Also, it is sturdy and capable of extended use without failure.
U.S. Pat No. 4,144,674 has a latch mechanism mounted externally of the window sash which is of interest.